The system of terraces of the river Seine is very complex on the continent from the source in eastern France to Le Havre, as well as on its immerged part, the English Channel, where there is a confluence with the palaeovalley of the river Somme and the Northern palaeovalley; downstream it is called the Channel River. The Seine can be divided into four main sections. The key section is between Elbeuf-Rouen and Le Havre, with big meanders and several well dated terraces. On the floor Channel, after the confluence, at the latitude of Cherbourg (the troughs of Cotentin) there are the deltaic infills of the Hurd Deep, the Celtic Banks and a deep sea fan in the Atlantic Ocean. Upstream of Elbeuf there are multiple small terraces covered by 16 identical sequences. Upstream of Paris, the system of terraces is again simple like at Rouen but the valley is flooded by a late glacial sandy loam unknown downstream.